Abstract
Cimyunnins A-C (1-3), characterized with an unusual fused cyclopentenone ring G, together with cimyunnin D (4), possessing a highly rearranged γ-lactone ring F, were characterized from the fruit of Cimicifuga yunnanensis. Their structures were elucidated by spectroscopic analysis, X-ray diffraction, and density functional theory calculations. In addition, cimyunnin A exhibited comparable anti-angiogenic activities to those of sunitinib, a clinically-used first-line angiogenesis inhibitor, in the in vitro and ex vivo studies.